Overwhelmed but ready for action, five aspiring space explorers learn they have the power to create Voltron, the most powerful robot in the universe.

When the Paladins are unable to form Voltron during a training session, Coran puts them through his own rigorous training in order to build a sense of brotherhood and trust between the Paladins. However, the Paladins fail miserably and are unable to connect. It is not until the Paladins engage in a food fight with Allura and Coran that they finally begin to work as a team and are successfully able to form Voltron.

As the Castle of Lions continues to prepare for departure, the team is met by the arrival of a local Arusian investigating the castle. Allura heads to meet the villagers along with Coran, Hunk, Keith and Lance while Pidge and Shiro tend to the rescued prisoners from the Galra battleship.

The team and Arusians celebrate Voltron's victory in the castle, but the festivities come to a halt when Pidge reveals his intentions to leave the team and search for his missing father and brother. As the team tries to convince Pidge to stay, Haxus, one of Sendak's soldiers, is able to sneak a bomb drone into the castle, causing it to destroy the crystal that powers the entire castle and severely injure Lance in the process.

Hunk and Coran meet local Balmerans, Shay and Rax, who help them hide from the Galra. Shay admires the two and wants to help them, but Rax is cautious and insists they leave. Hunk and Coran are able to sneak past the Galra to find a crystal, but are captured and imprisoned. Shay helps them escape with the crystal, but is captured by the Galra after her brother informs them of Shay's actions.

On the way to the Balmera, the team stops to help two rebels on the run from the Galra. Lance is trusting, but Hunk is skeptical of their intentions.

Allura, Coran and the Paladins return to the Balmera to free the natives, but the arrival of a Galra ship could force Voltron into action.

As the Paladins scramble to ward off a Galra monster, Allura hopes that her ancient powers can heal the Balmera and save its people.

Allura considers making a heartbreaking sacrifice to save the team when the castle mysteriously turns on them and sends them hurtling toward doom.

The team stops at an isolated and seemingly insignificant Galra space station and discovers how the empire is gathering its energy from the universe.

Zarkon lures Voltron into a battle on his ship, and when one of the lions is captured the team must get creative to defeat the Galra and return home.